Featured Research

In the war between parasite and host, the parasitic wasp and the pea aphid are locked in a battle for survival. New research shows that this cunning parasite sniffs out differences between protected and unprotected aphids, and alters its egg-laying strategy, in order to overwhelm aphid defenses and ensure survival of wasp offspring. The wasp lays an egg inside the pea aphid, where the egg hatches and converts the aphid's insides into a wasp nursery. The wasp larva uses the still-living aphid as a food source, eventually pupating inside the aphid and emerging as a fully-formed mature wasp. However the pea aphid is not defenseless. It is protected by a bacterial symbiont.

Share This

In the war between parasite and host, the parasitic wasp, Aphidius ervi, and the pea aphid, Acyrthosiphon pisum, are locked in a battle for survival. New research published in BioMed Central's open access journal BMC Biology shows that this cunning parasite sniffs out differences between protected and unprotected aphids, and alters its egg-laying strategy, in order to overwhelm aphid defenses and ensure survival of wasp offspring.

Related Articles

The wasp, A. ervi, lays an egg inside the pea aphid, where the egg hatches and converts the aphid's insides into a wasp nursery. The wasp larva uses the still-living aphid as a food source, eventually pupating inside the aphid and emerging as a fully-formed mature wasp. However the pea aphid is not defenseless. It is protected by a bacterial symbiont Hamiltonella defensa (and its associated bacteriophage APSE).

Although the wasps still lay their eggs, wasp larvae are unable to develop normally. Researchers from the Universities of Georgia and Arizona collaborated with researchers from Akita Prefectural University, Japan, to investigate what tactics the wasps might use to overcome the aphids' symbiont defense strategy. The researchers found that wasps which laid two eggs (superparasitism) in aphids infected with H. defensa and APSE were much more successful at producing live offspring.

However laying two eggs in uninfected hosts had little effect on the number of surviving wasps as only one wasp can complete development in each aphid. This suggests that having twice the amount of factors secreted by the developing wasp overpowers the protection due to bacterial infection, and is an adaption to ensure the survival of one wasp at the cost of two.

In a twist it seems that the wasps are able to work out which aphids are harboring the symbionts and which are not. Dr Kerry Oliver, who led this study, explained, "We discovered that A. ervi would preferentially lay two eggs in infected hosts, and a single egg if the aphids were unprotected. We don't for sure how wasps discriminate, but, when we looked for differences between the aphids, we found that infected aphids produced less of the compound trans-b-farnesene. This compound is a major component of aphid alarm pheromone and wasps are known to use this cue to find hosts."

Whatever the trick that they are using to work out which aphids are infected, wasps appear to be able to lay just enough eggs to stay ahead in the arms race.

More From ScienceDaily

More Plants & Animals News

Featured Research

Mar. 31, 2015  Soil organic matter, long thought to be a semi-permanent storehouse for ancient carbon, may be much more vulnerable to climate change than previously thought. Scientists have found that the common ... full story

Mar. 31, 2015  Using the assessment tool ForWarn, US Forest Service researchers can monitor the growth and development of vegetation that signals winter's end and the awakening of a new growing season. Now these ... full story

Mar. 31, 2015  Until now electric fences and trenches have proved to be the most effective way of protecting farms and villages from night time raids by hungry elephants. But researchers think they may have come up ... full story

Mar. 31, 2015  Researchers have detected a human fingerprint deep in the Borneo rainforest in Southeast Asia. Cold winds blowing from the north carry industrial pollutants from East Asia to the equator, with ... full story

Mar. 31, 2015  A team of engineers and biologists reports new progress in using computer modeling and 3D shape analysis to understand how the unique grasping tails of seahorses evolved. These prehensile tails ... full story

Mar. 31, 2015  As the five-year anniversary of the explosion of the Deepwater Horizon oil rig approaches, a new report looks at how twenty species of wildlife are faring in the aftermath of the ... full story

Mar. 31, 2015  Scientists have uncovered the earliest fossilized evidence of an insect caring for its young. The findings push back the earliest direct evidence of insect brood care by more than 50 million years, ... full story

Mar. 31, 2015  New research has scientists re-thinking how a lethal fungus grows and kills immune cells. The study hints at a new approach to therapy for Candida albicans, one of the most common causes of ... full story

Mar. 31, 2015  The most virulent strains of Streptococcus suis, the leading cause of bacterial meningitis in adult humans in parts of southeast Asia and in pigs around the world, are likely to have evolved and ... full story

Bionic Ants Could Be Tomorrow's Factory Workers

Reuters - Innovations Video Online (Mar. 30, 2015)  Industrious 3D printed bionic ants working together could toil in the factories of the future, says German technology company Festo. The robotic insects cooperate and coordinate their actions and movements to achieve a common aim. Amy Pollock reports.
Video provided by Reuters

Related Stories

June 2, 2014  Aphids are devastating insect pests and cause great losses to agriculture worldwide. These sap-feeding plant pests harbor in their body cavity bacteria, which are essential for the aphids' ... full story

Feb. 28, 2013  Previous studies have shown that carnivores can have indirect positive effects on each other, which means that when one species is lost, others could soon follow. Biologists have now found that ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.